If, as the saying goes, the body is a temple, then we are still discovery ever new secret chambers and passageways. In an unexpected discovery that reminds us that the human body is just full of surprises, researchers have learned that there are taste receptors not only in our mouths, but in our lungs as well.
A team of scientists at the University of Maryland School of Medicine in Baltimore set out to study the human lung muscle receptors that regulate the airway passages. By grinding up the lung muscle tissue and examining the genetic configuration of the chemical receptors, they found bitter-taste receptors in the lung tissue previously only known to be present on the tongue.
These receptors are structurally identical to the taste receptors on the tongue, except those on the tongue are clustered in taste buds that communicate with the brain. The receptors in the lungs only send messages to the smooth muscle cells. But both types respond to substances with a bitter flavor.
The researchers exposed bitter-tasting compounds to mouse and human airway tissues and found that it reopened closed airways in mere seconds. This result was the exact opposite of what they were expecting to prove. The theory they presupposed was that, because many plant-based toxins taste bitter, the lung’s taste receptors would cause a restricting response in the chest. This would result in coughing, thereby provoking the person to leave the area in which the inhalants were present. In other words, they thought it would trigger a reaction similar to an asthma attack.
When a person experiences an asthma attack, the involuntary muscles in the lungs tighten and constrict the airways, or bronchioles, that carry oxygen through the bloodstream to the rest of the body. This results in shortness of breath, coughing, and wheezing. The most common chronic disease in children, asthma is usually triggered by smoke, dust, dander, and other irritants.
But with each of the bitter substances the researchers tested on the lung tissue, the receptors were activated and opened the tubes of the lungs more significantly than any drug currently being used to treat asthma or chronic obstructive pulmonary disease (COPD).
While this is not a cure for asthma or any other lung disease because it does not deal with the inflammation or underlying causes of these illnesses, this finding does offer a new method of opening the airways of the lungs. It is an entirely different approach to treatment that could potentially replace or improve upon the drugs that are presently being prescribed, possibly leading to the creation of the first new breakthrough in asthma therapy in 50 years.
Unfortunately, eating bitter foods has no effect on the airways because the substances are not reaching the taste receptors of the lungs. Instead, bitters have to be broken down into a spray form that could be delivered through an inhaler and sent directly to the lungs in a strong concentration. Some of the compounds that the researchers used in lab experiments with success were quinine and chloquine, which are typically employed for the treatment of malaria, and the artificial sweetener saccharin.
Both the long- and short-acting types of bronchodialators presently used by the 23 million asthma sufferers in the United States are beta agonists. They single out the beta 2 adrenergic receptor, which works to expand constricted airways. But the bitter aerosols developed for this study opened the airways up to 90% of their original volume in a few seconds. These results were three times more effective than the beta 2 agonist inhalants used in the experiment.
The researchers also made a discovery about the involvement of calcium in the lungs. When the bitter substances came into contact with the lung muscles, the amount of calcium present rose and aided in the relaxation of the muscles. The taste receptors in the lungs seem to have their own stores of calcium to put to work.
All of this can provide quite a bit of food for thought for researchers and drug manufacturers alike, and hopefully will eventually lead to some major improvements in the way we treat asthma and other airway-related ailments. In the meantime, you can look at that bottle of Angostura Bitters in your liquor cabinet with newfound respect.